Forward Controls Design Blind Hole Enhanced Magazine Release Button Serrated Black EMR-HC Serrated. The form fitting curve along with horizontal serrations create a self centering surface that inhibits the finger's vertical movements. The EMR-HC has an uninterrupted surface and serrations its taller profile makes it easier to press and is only 0.04 taller than the factory magazine release button. When installed the EMR-HC has a 0.08 protrusion above the mag release button fence on most forged receivers. Due to the EMR-HC's installed height which protrudes 0.08in over the mag release fence when installed (only 0.06in or 0.07in of the magazine release button travel is needed to drop a magazine) EMR-HC is recommended for 7.62mm ARs only though it does work on 5.56mm ARs and M16s. For defense and duty ARs and M16s please use our EMR-H that has only a 0.01in protrusion over most forged receiver magazine release fence. For .308 ARs the EMR-HC's taller profile will allow you to use AR15/M16 spec mag catch and ambidextrous mag catch/release. An EMR-HC installed on a .308 AR will not protrude over the mag release fence. Specifications for Forward Controls Design Blind Hole Enhanced Magazine Release Button: Manufacturer: Forward Controls Design Gun Make: AR Platform Gun Model: AR-15 M16 Color: Black Fabric/Material: 4140 Steel Package Contents: Forward Controls Design Blind Hole Enhanced Magazine Release Button What firearm models does the manufacturer say Forward Controls Design Blind Hole Enhanced Magazine Release Button is compatible with? The manufacturer says that Forward Controls Design Blind Hole Enhanced Magazine Release Button is compatible with AR-15 M16Forward Controls Design EMR-HC Serrated: Blind Hole Enhanced Magazine Release Button Serrated Black